1. Field of the Invention
The invention relates to a separating device for a drive device that can be coupled to a movable structural component, such as a door leaf movable overhead, the separating device comprising a coupling element movable between a coupling position, in which it couples an output element of the drive device to the structural component, and a freewheeling position, in which the output element is decoupled from the structural component, and further comprising a locking member movable between at least one release position, in which it allows a movement of the coupling element into a freewheeling position, and at least one locking position, in which it counteracts a movement of the coupling element into the freewheeling position. The invention furthermore relates to a drive device provided with such a separating device as well as a door provided with such a drive device.
2. Description of the Related Art
Separating devices of the aforementioned kind are used in particular for operating electrically driven door leafs of garage doors or shop doors that are movable overhead. Drive devices for factory doors or shop doors with especially large and heavy door leafs are comprised generally of an electric motor and a gear with a greatly geared down transmission ratio which enables movement of heavy door leafs with electric motors of comparatively low power. Should the electric motor be inoperative because of a power outage or a defect, the door leaf must generally be decoupled from the drive device in order to enable a quick movement of the door leaf between its closed position and open position with a minimal force expenditure because the gear arranged between the electric motor and the door leaf is generally provided with a strong self-locking action counteracting this movement. For this reason, the drive device is coupled by means of a coupling element, movable between the coupling position and the freewheeling position, to the door leaf or a drive shaft for the door leaf. However, in order to protect the user of such doors, it must be ensured that the door leaf, upon movement of the coupling element into the freewheeling position, does not immediately drop into its closed position and thereby injure the user. For this reason, conventional separating devices of the aforementioned kind, as described in European patent 0 565 061 B1, are provided with a locking member which counteracts a movement of the coupling element into the freewheeling position and enables this movement only in a predetermined release position.
In the separating device described in the aforementioned document, the locking member is in the form of a lever which is supported to be rotatable about a predetermined axis and which engages in the locking position a circumferential groove of an actuating bolt for the coupling element and, in this way, prevents a movement of this coupling element into the freewheeling position. In the known device, the locking member is actuated by means of an adjusting member of a path simulator coupled to the drive device which is driven synchronously to the movement of the door leaf and provides a positional representation of the door leaf projected onto a small space. In this way, an actuation of the locking member from the locking position into the release position is carried out every time the adjusting member reaches the position corresponding to the closed position of the door leaf. The path simulator of the known device comprises a spindle coupled to the drive device and comprises a carriage engaging the thread of the spindle by means of a female thread. The carriage is guided on the thread of the spindle so as to be secured against rotation and is movable along the spindle axis. This carriage forms the adjusting member of the path simulator with which the locking member is actuated upon reaching the closed position of the door leaf. For this purpose, the carriage comprises a driver embodied in the form of a leaf spring which engages the locking member upon reaching the closed position of the door leaf.
With this arrangement it is possible to move the coupling element only into the freewheeling position when the door leaf is in the closed position, in which it rests on the floor of the room to be closed, while a movement of the coupling element otherwise is prevented by means of the locking member.
When using this known separating device comprising a locking member and a path simulator it was however found that a movement of the coupling element into a freewheeling position, even upon reaching the closed position of the door leaf, in particular after an extended time of operation or use of the door, is possible in some cases only with increased force expenditure or is not possible at all.